Clinical features and types of articular involvement in patients with psoriatic arthritis

Psoriatic arthritis (PsA) is a psoriasis-associated inflammatory arthritis which causes joint destruction. There are some epidemiologic data about PsA; however, there are no sufficient data from Turkey. Herein, we evaluated the frequency of PsA in the Thrace region of Turkey according to hospital-based data. In addition, we evaluated clinical features and types of joint involvement in PsA patients. We included 172 PsA patients fulfilling CASPAR criteria admitted to the Division of Rheumatology, Trakya University Medical Faculty, between 2003 and 2012. Data from Turkish Statistical Institution was used to calculate the incidence and prevalence of PsA. Patients' demographic features, durations of psoriasis and PsA, number of tender and swollen joints, treatment modalities, laboratory data, and X-ray film findings were recorded from hospital files. The annual incidence of PsA was 2.8/100,000. The mean annual incidence was 3.47/100,000 in females and 2.15/100,000 in males. The overall prevalence of PsA in our region was 27.9/100,000 (95 % confidence interval (CI) 23.7-32.1) in individuals >16 years. The prevalence of PsA was higher in females than in males (34.7/100,000 vs. 21.5/100,000). Polyarthritis was present in 67 (38.9 %), oligoarthritis in 47 (27.3 %), spondyloarthritis in 39 (22.6 %), and distal interphalangeal (DIP) arthritis in 19 (11.0 %) patients. The duration of psoriasis was significantly longer in polyarticular PsA patients than in DIP and oligoarticular groups (p values = 0.016 and 0.018, respectively). The number of swollen joints correlated with age (r = 0.21, p = 0.006), duration of psoriasis (r = 0.20, p = 0.01), number of tender joints (r = 0.92, p ≤ 0.001), ESR (r = 0.24, p = 0.001), and CRP (r = 0.17, p = 0.026). The frequency of PsA in Thrace region is similar to that in low-frequency regions. The most frequent type of involvement was polyarticular, and it correlated with the duration of psoriasis and erosive disease.